ESDU 82001 provides an introduction to terminology used for acoustic quantities and their relationships and further provides general guidance on the principles of noise control in ventilation and air-conditioning systems, and similar types of ducting systems. Data are provided on room acoustic characteristics, including values of absorption coefficients for typical room surface materials and fittings, that are required for the estimation of sound pressure levels within the room. Noise criteria and acoustic factors that should be taken into consideration in the design of ventilation and air-conditioning systems are also discussed.